This invention relates to a structural column having a cruciform cross section and to a cooling tower which is supported by such columns.
Cooling towers are used to cool liquid by contact with air. The liquid is allowed to flow downwardly through the tower, and a counter current flow of air is drawn through the falling liquid by various means. A common application for liquid cooling towers is for cooling water (dissipating waste heat) used in electrical generating and process plants and industrial and institutional air conditioning systems.
Most cooling towers include a tower structure which encloses a fill material. The fill material has spaces through which the liquid flows downwardly and the air flows upwardly to provide heat and mass transfer between the liquid and the air. The tower structure may be formed from concrete, metal, or other material.
Metal parts of cooling towers can be corroded by the local atmosphere and/or the liquid which is being cooled. Concrete is very durable, but concrete towers are expensive and heavy. Many cooling towers are located on roofs of buildings, and the weight of a concrete cooling tower can cause building design problems. Co-owned U.S. Pat. No. 4,382,046 refers to a cooling tower with concrete walls which are supported above a concrete water basin by concrete supports.
Plastic parts are resistant to corrosion, but plastic parts ordinarily would not provide enough strength to support the fill material and the weight of the tower itself. One well-known type of fill material which is used by Ceramic Cooling Towers of Forth Worth, Tex. consists of stacked layers of open-celled clay tiles. This fill material can weight 60,000 to 70,000 pounds for a conventional size air conditioning cooling tower. Structural parts of a cooling tower must not only support the weight of the fill material but must also resist wind forces and should be designed to withstand earthquake loads.
Co-owned U.S. Pat. No. 4,422,983 describes a cooling tower formed from fiberglass reinforced polyester resin panels and beams. All of the structural parts of the tower are fiberglass reinforced polyester resin except the cast iron lintels which are used to support the fill material and stainless steel bolts which connect the fiberglass reinforced polyester resin parts.
Co-owned U.S. Pat. No. 4,543,218 describes a cooling tower in which the weight of the tower and the fill material is supported by precast concrete support legs and the basin is concrete. A liquid supply pipe extends vertically upwardly through the fill material and supports the weight of the fan.
Co-owned U.S. Pat. No. 4,637,903 describes a lightweight cooling tower in which all of the structural components are formed from fiberglass reinforced polyester resin, and the fill material is supported directly by the basin.
The cooling towers described in the foregoing patents had many advantages over prior cooling towers. However, many customers of cooling towers continue to purchase wood towers. The advantage of a wood tower is that the wood is inexpensive and is easy to fabricate and ship. However, wood towers are difficult to assemble and are prone to rotting. The average life of a wood tower is only about 7 to 10 years, and maintenance costs are high.